Power supply



FIG. 1 is a perspective view showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a back view thereof;

FIG. 4 is a top plan view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a left side view thereof; and,

FIG. 7 is a right side view thereof.

The portions of the power supply shown in broken lines are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a power supply, as shown and described. 